Productivity, profitability and resilience

DETERMINING HOW MANAGEMENT AFFECTS SOIL HEALTH

PHOTO: LYSIMETER IN A FIELD AT THE SOIL HEALTH INTERPRETIVE CENTRE IN ELORA.

NEW HIGH TECH monitors will help take the guesswork out of best management practices for grain crops as they relate to soil health in a groundbreaking study funded by Grain Farmers of Ontario.

While there is plenty of scientific research into various aspects of soil health, there has never been a comprehensive look at how using different management practices affect a crop’s productivity, profitability, and resilience to weather events caused by climate change — until now.

The five-year study was launched in May 2016 at the University of Guelph’s new Soil Health Interpretive Centre in Elora. The centre is the first of its kind in Canada and the study is one of several projects being carried out there.

Professor Claudia Wagner-Riddle and Professor Alfons Weersink of the University of Guelph are the “Environmental and Economic Value of Soil Services” project co-leads.

“We want to quantify the benefits of improving soil health from a productivity and economic point of view,” says Wagner-Riddle.

The three main objectives of the study are to:
• find out how diverse crop rotations compare to conventional rotations in terms of nitrogen supply, productivity, and water conservation;
• figure out the profitability and relative advantage of diverse versus conventional crop systems; and
• identify the implications of severe weather events on the costs and benefits of diverse versus conventional cropping.

Rather than the standard agronomic research procedure of testing several locations, this study will be conducted entirely at the centre using 18 high-tech lysimeters. The system — a first for North America — was purchased for $2 million from Hoskins Scientific, Canada (equipment manufactured by UMS, Germany). Funding for the equipment was provided by the Canadian Foundation for Innovation and the Ontario Ministry of Research, Innovation and Science.

LYSIMETERS

The lysimeters are large underground steel cylinders encased in concrete tubes that have sensors placed at different levels. Nine lysimeters contain undisturbed loam from the Elora Centre and nine have a sandy loam soil brought from Cambridge.

They are extremely sensitive, taking measurements every minute for some variables and for others, every ten minutes.

“A lot of changes happen to the soil during a big rainfall event and they happen quickly,” says Wagner-Riddle. “We don’t know when exactly the event will happen, so by measuring all the time, we won’t miss it.”

Data gathered from the lysimeters is aggregated and studied by the researchers.

This research will provide a side-by-side comparison of a conventional rotation of corn-soybean-soybean with a diversified rotation of corn-soybean-wheat plus some cover crops, which are still being decided.

“We want to understand the underlying factors so that in the future we can apply those concepts to other types of rotations,” she says.

ECONOMIC IMPACT

The second, economic aspect of the study will begin in year three of the study, when Weersink will try to determine if there are trade-offs in terms of crop productivity and profitability with more diverse crop rotations. He will also look at what other benefits come from this kind of crop management, for example, if there is a reduced need for nitrogen inputs.

Weersink will also investigate mechanisms by which producers could be compensated for soil ecosystem services — for example enhancing water quality and providing carbon sinks.

Under the project’s third objective, related to severe weather events, Wagner-Riddle’s hypothesis is that diversified systems are more resilient to extreme conditions, such as drought, caused by climate change.

This research will combine the detailed data sets from the lysimeters showing what’s happening in the soil and plants with mathematical computer modeling. The researchers will then use the models to run different weather scenarios to see what might happen over a 30-year period.

“First we have to calibrate and validate what we have in the field so we can increase our confidence in what the models are doing,” Wagner-Riddle says.

The researchers hope to provide grain producers with management choices that will increase the sustainability of their crops, help identify the most cost-effective policies and programs to support sustainability goals, and find ways to protect crops against environmental stressors.

By 2021, the research will hopefully tell scientists, farmers, government policy makers, and others whether and how much diversified crop systems add to the productivity, resilience, and economic value of grain crops in Ontario. •

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